1. Field of the Invention
The present invention relates to a displacement detection apparatus used to detect linear displacement, rotational displacement, etc., in a machine tool, an industrial machine, a robot, etc., and particularly relates to a displacement detection apparatus configured to detect displacement in a plurality of directions.
2. Description of the Related Art
Conventionally, a displacement detection apparatus is used to detect an amount of linear movement, a linear position, an amount of rotational movement, and a rotation angle for intended purposes, such as positioning, controlling, and displaying a position of a machine tool, an industrial machine, a robot, etc. In recent years, a displacement detection apparatus capable of detecting a positional deviation of a uniaxial moving stage, that is, an amount of displacement in a plurality of directions is demanded.
As a displacement detection apparatus capable of detecting an amount of displacement in a plurality of directions, for example, the one described in Patent Literature 1 is known. This displacement detection apparatus has a magnetic scale on which a first magnetized part magnetized as an N pole and a second magnetized part magnetized as an S pole are sequentially arranged alternately on a two-dimensional plane, and a magneto-electric converting device that moves on the magnetic scale. Then, on the magnetic scale, a two-dimensional magnetic grating is formed by the first magnetized part and the second magnetized part.    [Patent Literature 1] Japanese Patent Laid-Open No. 1993-89480